I have a simple setup, a 20 gallon FW tank with two Walmart power filters on the back. The tank was in excess of 84 degrees due to room temp, though the room temp wasn't even close to that. I moved it to the basement, which is full depth and is no warmer than 70 during the middle of the summer. The tank won't get lower than 82 degrees now, and it's not the heaters (I unplugged one heater and they are set at 78) . Is this to be expected? I would think that the temp would drop at least into the 70's given the ambient temp. Could the power filters be heating it up this much? I don't know what else to do, and can't afford a chiller.